ACPI/processor: Convert to hotplug state machine

Install the callbacks via the state machine.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-acpi@vger.kernel.org
Cc: rt@linutronix.de
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/20160906170457.32393-12-bigeasy@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/acpi/processor_driver.c

@@ -110,55 +110,46 @@ static void acpi_processor_notify(acpi_handle handle, u32 event, void *data)
 
 static int __acpi_processor_start(struct acpi_device *device);
 
-static int acpi_cpu_soft_notify(struct notifier_block *nfb,
-					  unsigned long action, void *hcpu)
+static int acpi_soft_cpu_online(unsigned int cpu)
 {
-	unsigned int cpu = (unsigned long)hcpu;
 	struct acpi_processor *pr = per_cpu(processors, cpu);
 	struct acpi_device *device;
-	action &= ~CPU_TASKS_FROZEN;
-
-	switch (action) {
-	case CPU_ONLINE:
-	case CPU_DEAD:
-		break;
-	default:
-		return NOTIFY_DONE;
-	}
 
 	if (!pr || acpi_bus_get_device(pr->handle, &device))
-		return NOTIFY_DONE;
+		return 0;
+	/*
+	 * CPU got physically hotplugged and onlined for the first time:
+	 * Initialize missing things.
+	 */
+	if (pr->flags.need_hotplug_init) {
+		int ret;
 
-	if (action == CPU_ONLINE) {
-		/*
-		 * CPU got physically hotplugged and onlined for the first time:
-		 * Initialize missing things.
-		 */
-		if (pr->flags.need_hotplug_init) {
-			int ret;
-
-			pr_info("Will online and init hotplugged CPU: %d\n",
-				pr->id);
-			pr->flags.need_hotplug_init = 0;
-			ret = __acpi_processor_start(device);
-			WARN(ret, "Failed to start CPU: %d\n", pr->id);
-		} else {
-			/* Normal CPU soft online event. */
-			acpi_processor_ppc_has_changed(pr, 0);
-			acpi_processor_hotplug(pr);
-			acpi_processor_reevaluate_tstate(pr, action);
-			acpi_processor_tstate_has_changed(pr);
-		}
-	} else if (action == CPU_DEAD) {
-		/* Invalidate flag.throttling after the CPU is offline. */
-		acpi_processor_reevaluate_tstate(pr, action);
+		pr_info("Will online and init hotplugged CPU: %d\n",
+			pr->id);
+		pr->flags.need_hotplug_init = 0;
+		ret = __acpi_processor_start(device);
+		WARN(ret, "Failed to start CPU: %d\n", pr->id);
+	} else {
+		/* Normal CPU soft online event. */
+		acpi_processor_ppc_has_changed(pr, 0);
+		acpi_processor_hotplug(pr);
+		acpi_processor_reevaluate_tstate(pr, false);
+		acpi_processor_tstate_has_changed(pr);
 	}
-	return NOTIFY_OK;
+	return 0;
 }
 
-static struct notifier_block acpi_cpu_notifier = {
-	    .notifier_call = acpi_cpu_soft_notify,
-};
+static int acpi_soft_cpu_dead(unsigned int cpu)
+{
+	struct acpi_processor *pr = per_cpu(processors, cpu);
+	struct acpi_device *device;
+
+	if (!pr || acpi_bus_get_device(pr->handle, &device))
+		return 0;
+
+	acpi_processor_reevaluate_tstate(pr, true);
+	return 0;
+}
 
 #ifdef CONFIG_ACPI_CPU_FREQ_PSS
 static int acpi_pss_perf_init(struct acpi_processor *pr,
@@ -303,7 +294,7 @@ static int acpi_processor_stop(struct device *dev)
  * This is needed for the powernow-k8 driver, that works even without
  * ACPI, but needs symbols from this driver
  */
-
+static enum cpuhp_state hp_online;
 static int __init acpi_processor_driver_init(void)
 {
 	int result = 0;
@@ -315,11 +306,22 @@ static int __init acpi_processor_driver_init(void)
 	if (result < 0)
 		return result;
 
-	register_hotcpu_notifier(&acpi_cpu_notifier);
+	result = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					   "acpi/cpu-drv:online",
+					   acpi_soft_cpu_online, NULL);
+	if (result < 0)
+		goto err;
+	hp_online = result;
+	cpuhp_setup_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD, "acpi/cpu-drv:dead",
+				  NULL, acpi_soft_cpu_dead);
+
 	acpi_thermal_cpufreq_init();
 	acpi_processor_ppc_init();
 	acpi_processor_throttling_init();
 	return 0;
+err:
+	driver_unregister(&acpi_processor_driver);
+	return result;
 }
 
 static void __exit acpi_processor_driver_exit(void)
@@ -329,7 +331,8 @@ static void __exit acpi_processor_driver_exit(void)
 
 	acpi_processor_ppc_exit();
 	acpi_thermal_cpufreq_exit();
-	unregister_hotcpu_notifier(&acpi_cpu_notifier);
+	cpuhp_remove_state_nocalls(hp_online);
+	cpuhp_remove_state_nocalls(CPUHP_ACPI_CPUDRV_DEAD);
 	driver_unregister(&acpi_processor_driver);
 }
 

drivers/acpi/processor_throttling.c

@@ -375,11 +375,11 @@ int acpi_processor_tstate_has_changed(struct acpi_processor *pr)
  *	3. TSD domain
  */
 void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
-					unsigned long action)
+					bool is_dead)
 {
 	int result = 0;
 
-	if (action == CPU_DEAD) {
+	if (is_dead) {
 		/* When one CPU is offline, the T-state throttling
 		 * will be invalidated.
 		 */

include/acpi/processor.h

@@ -359,7 +359,7 @@ extern int acpi_processor_set_throttling(struct acpi_processor *pr,
  * onlined/offlined. In such case the flags.throttling will be updated.
  */
 extern void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
-			unsigned long action);
+			bool is_dead);
 extern const struct file_operations acpi_processor_throttling_fops;
 extern void acpi_processor_throttling_init(void);
 #else
@@ -380,7 +380,7 @@ static inline int acpi_processor_set_throttling(struct acpi_processor *pr,
 }
 
 static inline void acpi_processor_reevaluate_tstate(struct acpi_processor *pr,
-			unsigned long action) {}
+			bool is_dead) {}
 
 static inline void acpi_processor_throttling_init(void) {}
 #endif	/* CONFIG_ACPI_CPU_FREQ_PSS */

include/linux/cpuhotplug.h

@@ -25,6 +25,7 @@ enum cpuhp_state {
 	CPUHP_IRQ_POLL_DEAD,
 	CPUHP_BLOCK_SOFTIRQ_DEAD,
 	CPUHP_VIRT_SCSI_DEAD,
+	CPUHP_ACPI_CPUDRV_DEAD,
 	CPUHP_WORKQUEUE_PREP,
 	CPUHP_POWER_NUMA_PREPARE,
 	CPUHP_HRTIMERS_PREPARE,